What's the Internet:a service view ▣communication infrastructure(下部胸造) enables distributed(分布式的) applications: Web,email,games,e- commerce,file sharing communication services provided to apps: Connectionless unreliable connection-oriented reliable Introduction 1-7 Introduction 1-7 What’s the Internet: a service view ❑ communication infrastructure （下部构造） enables distributed（分布式的） applications: ❖ Web, email, games, e￾commerce, file sharing ❑ communication services provided to apps: ❖ Connectionless unreliable ❖ connection-oriented reliable